Method of authenticating integrated circuits using optical characteristics of physically unclonable functions

ABSTRACT

A method and apparatus for reading unique identifiers of an integrated circuit. The unique identifiers may be physically unclonable functions (PUFs), formed by high energy ions implanted into semiconductor material of the integrated circuit. The method may include electrically or optically stimulating each of the PUFs and sensing with an optical sensor optical characteristics of resulting light emitted from the PUFs. Then the method may include comparing values associated with the optical characteristics of the PUFs with groups of stored values in a circuit database. Each of the groups of stored values may be associated with optical characteristics of PUFs of a known authentic circuit. The method may then include the controller providing verification of authenticity of the integrated circuit when each of the values associated with the optical characteristics of the PUFs match the stored values of at least one of the groups in the circuit database.

RELATED APPLICATIONS

The present application is a continuation application and claimspriority of co-pending application titled “METHOD OF AUTHENTICATINGINTEGRATED CIRCUITS USING OPTICAL CHARACTERISTICS OF PHYSICALLYUNCLONABLE FUNCTIONS”, Ser. No. 14/973,383, filed Dec. 17, 2015, thecontent of which is hereby incorporated by reference in its entirety.

STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT

-   -   This invention was made with Government support under Contract        No.: DE-NA-0002839 awarded by the United States Department of        Energy/National Nuclear Security Administration. The Government        has certain rights in the invention.

BACKGROUND

Detecting counterfeit electronics, such as integrated circuits, is animportant challenge facing many companies, because such counterfeitingcan cause significant economic losses. Unfortunately, detectingcounterfeit integrated circuits is difficult because such circuits aremounted inside electronic devices.

One anti-counterfeit method uses an electrical process in whichvariations in fabrication of the circuit lead to variations inelectrical properties. These variations, often referred to as physicallyunclonable functions (PUFs), are then used as identifiers.Unfortunately, these PUFs require operation of the integrated circuitdevice in order to function properly. This, in turn, requiresfabrication of a complex integrated circuit, thus making it obvious tonon-authorized entities that the device has been identified as importantenough to protect. Another disadvantage of these types of PUFs is thatthey can only be used in Si CMOS circuits, due to the digital circuitryand memory requirements for identification of these PUFs.

Thus, there is a need for a simplified and more discreet method ofverifying the authenticity of integrated circuits.

SUMMARY OF THE INVENTION

Embodiments of the present invention solve the above-mentioned problemsand provide a distinct advance in the art of verifying the authenticityof integrated circuits.

One embodiment of the invention is a method of reading uniqueidentifiers of an integrated circuit to detect authenticity of thecircuit. The unique identifiers may be physically unclonable functions(PUFs). Specifically, the PUFs may include high energy ions implantedinto crystal lattices of semiconductor material of the integratedcircuit at a plurality of locations, each location forming one of thePUFs having unique associated damage. The method may include a step ofelectrically or optically stimulating each of the PUFs and sensing withan optical sensor optical characteristics of light emitted from the PUFswhen optically stimulated. Then the method may include a step ofcomparing values associated with the optical characteristics of the PUFswith one or more groups of stored values in a circuit database. Each ofthe groups of stored values in the circuit database may be associatedwith optical characteristics of PUFs of a known authentic circuit. Themethod may further include a step of providing verification ofauthenticity of the integrated circuit when each of the valuesassociated with the optical characteristics of the PUFs match the storedvalues of at least one of the groups in the circuit database.

In some embodiments of the invention, the optical characteristics of thePUFs of the integrated circuit may include wavelength, intensity, and/ortotal area of the light received with the optical sensor from each ofthe PUFs of the integrated circuit. The step of providing verificationof authenticity may include providing an audible or visual indication ofthe authenticity of the integrated circuit. Furthermore, in someembodiments of the invention, the method may further include a step ofproviding an audible or visual indication that the integrated circuit isa counterfeit circuit when each of the values associated with theoptical characteristics of the PUFs do not match the stored values of atleast one of the groups in the circuit database.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Other aspectsand advantages of the current invention will be apparent from thefollowing detailed description of the embodiments and the accompanyingdrawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Embodiments of the current invention are described in detail below withreference to the attached drawing figures, wherein:

FIG. 1 is a schematic cross-sectional view of an integrated circuitconstructed according to embodiments of the present invention,illustrating light emitting from a dislocation loop area;

FIG. 2 is a top view of the integrated circuit of FIG. 1, illustratingion implant regions or physically unclonable functions (PUFs) withvarying material properties;

FIG. 3 is a block diagram of an authentication apparatus for analyzinglight emitted from the PUFs;

FIG. 4 is a flow chart illustrating a method of marking an integratedcircuit with PUFs in accordance with embodiments of the presentinvention; and

FIG. 5 is a flow chart illustrating a method of detecting anddeciphering PUFs on the integrated circuit in accordance withembodiments of the present invention.

The drawing figures do not limit the current invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following detailed description of the invention references theaccompanying drawings that illustrate specific embodiments in which theinvention can be practiced. The embodiments are intended to describeaspects of the invention in sufficient detail to enable those skilled inthe art to practice the invention. Other embodiments can be utilized andchanges can be made without departing from the scope of the currentinvention. The following detailed description is, therefore, not to betaken in a limiting sense. The scope of the current invention is definedonly by the appended claims, along with the full scope of equivalents towhich such claims are entitled.

In this description, references to “one embodiment”, “an embodiment”, or“embodiments” mean that the feature or features being referred to areincluded in at least one embodiment of the technology. Separatereferences to “one embodiment”, “an embodiment”, or “embodiments” inthis description do not necessarily refer to the same embodiment and arealso not mutually exclusive unless so stated and/or except as will bereadily apparent to those skilled in the art from the description. Forexample, a feature, structure, act, etc. described in one embodiment mayalso be included in other embodiments, but is not necessarily included.Thus, the current technology can include a variety of combinationsand/or integrations of the embodiments described herein.

Embodiments of the invention, illustrated in FIGS. 1-5, include anauthentication apparatus 28 and method for detecting and decipheringunique identifiers on an integrated circuit 10. As illustrated in FIG.1, the integrated circuit 10 may comprise one or more semiconductormaterials 12 such as any combination of Si, SiGe, GaAs, and/or GaN. Insome embodiments of the invention, the semiconductor materials 12 mayhave a conductive metal 14 such as aluminum or other conductivematerials known in the art applied to the bottom of the semiconductormaterials 12 and may have one or more layers of a dielectric material16, such as silicon dioxide (SiO₂) applied over the semiconductormaterials 12, as illustrated in FIG. 1. Note that aluminum and otherconductive metals may also be used at other locations on the integratedcircuit 10, forming various electrical devices 18, components, andconnections thereon.

The semiconductor materials 12 may include crystal lattices into whichhigh energy ions 20 may be implanted during integrated circuitfabrication. The ions 20 implanted into the crystal lattices mayinclude, for example, boron and/or phosphorus, as illustrated in FIG. 1.Defect areas created by this ion implantation may include amorphousregions. After annealing, the amorphous regions may recrystallize, witha large number of line defects or dislocation loops 22. Thesedislocation loops 22 may be responsible for emitting light 24 havingspecific emission spectra when electrically or optically stimulated, asdescribed below.

As illustrated in FIG. 2, the integrated circuit 10 may include aplurality of locations at which the high energy ions 20 are implanted.At each of these locations, the implanted ions 20 may form areas ofdefect which can emit light, similar to a micro-scale light emittingdiode (LED), when electrically or optically stimulated. Specifically,the resulting damage at each of these locations may be referred toherein as unique identifiers or physically unclonable functions (PUFs)26. The PUFs 26 are represented in FIG. 2 with different patternsrepresenting small random changes in material properties due to varyingacceleration energy, ion dose, and/or beam size used in the creation ofthe PUFs 26. These resulting material variations can include ion implantconcentration, how many atoms are implanted, ion implant depth, numberof dislocation loops 22, and/or a size of an area that is implanted foreach of the PUFs 26. Dislocation loops 22 may be defined herein as linedefects in the semiconductor material 12, or an extra line of atomsinserted between two other lines of atoms and completely contained inthe crystal lattice. The higher the dose or the higher the accelerationenergy used during ion implantation, the more dislocation loops 22created.

At least some of the PUFs 26 on the integrated circuit 10 may havediffering optical properties than others when electrically or opticallystimulated, resulting in electroluminescence or photoluminescence, basedon their differing material properties described above. The resultingintensity, wavelength, or any other optical properties of the light 24emitted by the PUFs 26 may be logged or recorded in a database for laterverification of the authenticity of the integrated circuit 10. Forexample, the plurality of locations implanted with PUFs 26 may includesixty-four discrete areas, cooperatively providing a sixty-four digitkey serving as a circuit authentication identifier for the circuit 10.In FIG. 2, eight PUFs 26 are illustrated, each of which may representspecific values and/or specific optical properties measured and storedin a database for a particular manufacturer or authentication agency.

In some embodiments of the invention, the implantation of the ions 20 toform the PUFs 26 may be performed by an ion implantation device (notshown). The ion implantation device may include standard semiconductorfabrication tools known in the art, such as an ion implanter, focusedion beam tools, or any other device(s) known in the art for creatingsmall random changes in material properties of the circuit's crystallattice. Furthermore, the ion implantation device may be configured tomanually of automatically vary acceleration energy, ion dose, and/orbeam size in order to vary the resulting material properties of the PUFs26 to be measured and identified, as later described herein.

Some embodiments of the invention, as illustrated in FIG. 3, may includean authentication apparatus 28 configured to document the PUFs 26 and/orauthenticate the integrated circuit 10 using PUF data stored in acircuit database 30. The authentication apparatus 28 may include anoptical sensor 32, the circuit database 30, and/or a controller 34configured to receive optical measurements from the optical sensor 32and to compare those measurements with circuit authenticationinformation stored in the circuit database 30.

The optical sensor 32 may be any one or more sensors configured tomeasure an amount of light intensity and wavelength emitted from thePUFs 26. For example, the PUFs 26 may emit light via electroluminescence(i.e., emitting light in response to the passage of an electric currentor to a strong electric field) or photoluminescence (emitting light inresponse to photoexcitation of photons in the PUFs). One or more energysources (not shown) configured for creating the electroluminescence orphotoluminescence described above may be used in conjunction with theoptical sensor 32 and/or may be integrated into a housing of the opticalsensor 32. In use, the optical sensor 32 may be positioned relative tothe circuit 10 in a location close enough to receive and quantify thelight 24 emitted from the PUFs 26 when stimulated electrically oroptically. The optical sensor 32 may also be communicatively coupledwith the controller 34, to send information related to the emitted light26 back to the controller 34 to be analyzed.

The circuit database 30, as illustrated in FIG. 3, may compriseresidential or external memory that may be integral with the controller34, stand-alone memory, or a combination of both. The memory mayinclude, for example, removable and non-removable memory elements suchas RAM, ROM, flash, magnetic, optical, USB memory devices, MMC cards, RSMMC cards, SD cards such as microSD or miniSD, SIM cards, and/or othermemory elements. The circuit database 30 may store, for example, keys,codes, variables, or other values corresponding to optical propertiesand/or material properties of the PUFs 26 of one or more circuits. Thesestored values may include values associated with intensity of theemitted light 24, wavelength of the emitted light 24, and/or a size ofan area that is implanted with the ions 20.

The controller 34 may comprise any number of combination of processors,circuits, integrated circuits, programmable logic devices such asprogrammable logic controllers (PLC) or motion programmable logiccontrollers (MPLC), computers, processors, microcontrollers,transmitters, receivers, other electrical and computing devices, and/orresidential or external memory for storing data and other informationabout the optical sensor 32 and/or the PUFs 26. The controller 34 maycontrol operation of the optical sensor 32 and/or receive signalscorresponding to light 24 sensed thereby, including intensity andwavelength measurements to be stored in the circuit database 30 duringthe manufacturing stage and then later compared to values stored in thecircuit database 30 to determine authenticity of the circuit 10.

The controller 34 may be configured to implement any combination ofalgorithms, subroutines, computer programs, or code corresponding tomethod steps and functions described herein. The controller 34 andcomputer programs described herein are merely examples of computerequipment and programs that may be used to implement the presentinvention and may be replaced with or supplemented with othercontrollers and computer programs without departing from the scope ofthe present invention. While certain features are described as residingin the controller 34, the invention is not so limited, and thosefeatures may be implemented elsewhere. For example, one or more of thecircuit databases 30 may be remotely accessed by the controller 34 forretrieving PUF-related measurements without departing from the scope ofthe invention.

The controller 34 may implement the computer programs and/or codesegments to perform various method steps described herein. The computerprograms may comprise an ordered listing of executable instructions forimplementing logical functions in the controller. The computer programscan be embodied in any computer-readable medium for use by or inconnection with an instruction execution system, apparatus, or device,and execute the instructions. In the context of this application, a“computer-readable medium” can be any physical medium that can contain,store, communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The computer-readable medium can be, for example, but not limited to, anelectronic, magnetic, optical, electro-magnetic, infrared, orsemi-conductor system, apparatus, or device. More specific, although notinclusive, examples of the computer-readable medium would include thefollowing: an electrical connection having one or more wires, a portablecomputer diskette, a random access memory (RAM), a read-only memory(ROM), an erasable, programmable, read-only memory (EPROM or Flashmemory), a portable compact disk read-only memory (CDROM), an opticalfiber, multi-media card (MMC), reduced-size multi-media card (RS MMC),secure digital (SD) cards such as microSD or miniSD, and a subscriberidentity module (SIM) card.

In some embodiments of the invention, the authentication apparatus 28may further comprise and/or be communicably coupled with a notificationdevice 36, such as a user interface, visual display device, and/orspeaker, any of which may communicate to a user, visually or audibly.For example, the visual display device may be a computer screen or maysimply be one or more LEDs configured to visually indicate if theintegrated circuit 10 is determined by the controller 34 to be authenticor counterfeit. Additionally or alternatively, the speaker may beconfigured to output an audible indication to the user regarding theauthenticity of the integrated circuit 10. In some embodiments of theinvention, the notification device 36 may further include a wirelesstransmitter configured to transmit information from the controller 34 toa remote notification device, such as another computer, tablet, smartphone, or the like.

In use, the integrated circuit 10 may be tagged and identified at thewafer scale during fabrication. For example, the authenticationapparatus 28 may measure and record optical characteristics of thecircuit 10 in the circuit database 30. Then, to later verify theauthenticity of the circuit 10, the authentication apparatus 28 mayagain measure the optical characteristics of the circuit 10 and comparethose optical characteristics to those earlier recorded and stored inthe circuit database 30. The authentication apparatus 28 may thencommunicate to a user whether or not the circuit 10 is authentic or is acounterfeit circuit. That is, if the optical characteristics measured donot correspond with any of the measurements recorded or otherwise storedin the circuit database 30, the authentication apparatus 28 may identifythe circuit 10 as a counterfeit.

Method steps for marking and/or identifying unique identifiers or PUFs26 on the integrated circuits 10 will now be described in more detail,in accordance with various embodiments of the present invention. Thesteps of the methods 400 and 500 may be performed in the order as shownin FIGS. 4 and 5, or they may be performed in a different order.Furthermore, some steps may be performed concurrently as opposed tosequentially. In addition, some steps may not be performed.

As illustrated in FIG. 4, the method 400 of marking circuits, such asthe integrated circuit 10, with unique identifiers or PUFs may include astep of implanting the high energy ions 20 into crystal lattices of thesemiconductor material 12 of the circuit 10 at a plurality of locationsusing ion implanters and/or focused ion beam tools, as depicted in block402. This may be done to improve conductivity of certain regions, toisolate devices of the circuit 10 from each other, and/or tointentionally create the PUFs 26 described herein. Because of slightvariations in the fabrication process, each resulting defect center orPUF 26 is unique, with a specific light emission intensity andwavelength. Thus, at least some of the PUFs 26 may have differingoptical properties than others of the PUFs 26 when electrically oroptically stimulated. In the integrated circuit 10 depicted in FIG. 2,eight discrete areas of damage may be associated with an eight-digit keyserving as a circuit authentication identifier. However, in anotherembodiment of the invention, the plurality of locations implanted withPUFs 26 may include sixty-four discrete areas, cooperatively providing asixty-four digit key serving as the circuit authentication identifierfor that circuit. Any number of PUFs 26 may be formed on the integratedcircuit 10 without departing from the scope of the invention.

In some embodiments of the invention, the method 400 may also include astep of varying acceleration energy, ion dose, and/or beam size used forcreation of the PUFs 26, as depicted in block 404, thereby affecting howdeep the ions 20 are implanted, how many atoms are implanted, and/or asize of an area that is implanted for each of the PUFs 26. Thesecharacteristics of the PUFs 26 may in turn affect intensity andwavelength output by these PUFs 26 when optically stimulated.Furthermore, the method 400 may include a step of testing anddocumenting optical characteristics of the PUFs 26 for each circuit, asdepicted in block 406. For example, for each known authentic circuit, agroup of values associated with optical characteristics of PUFs of thatknown authentic circuit may be stored in the circuit database 30.Additionally or alternatively, intensity and wavelength measurements foreach of the PUFs 26 may be determined and stored in the circuit database30 for a particular company, industry, or agency, to be looked up forlater authentication.

As illustrated in FIG. 5, the method 500 of detecting and decipheringthe unique identifiers or PUFs 26 on the circuits, such as theintegrated circuit 10, may include the steps of electrically oroptically stimulating each of the PUFs 26, as depicted in block 502, andsensing with the optical sensor 32 optical characteristics of light 24emitted from the PUFs 26 when electrically or optically stimulated, asdepicted in block 504. This may be done automatically via commands fromthe controller 34 or may be accomplished manually by a user shininglight and positioning the optical sensor 32 at a desired locationrelative to the circuit 10 to detect the PUFs 26. Note that somemanufacturers may chose a specific region on the circuits in which toimplant the ions 20 forming these PUFs 26. Thus, authorizing personneland/or the authentication apparatus 28 would be provided informationregarding where the light source and/or the optical sensor 32 must beplaced in relation to these PUFs 26 in order to properly measure theiroptical properties.

Next, the method 500 may include a step of comparing values associatedwith the optical characteristics of the PUFs 26 with one or more groupsof stored values in the circuit database 30, as depicted on block 506.For example, the comparing step 506 may include determining awavelength, intensity, and/or total area of light received with theoptical sensor 32 from each of the PUFs 26, and then assigning a valueto each of the PUFs based on those optical characteristics. This valuemay be assigned based on an algorithm solved using one or more of thoseoptical characteristics or based on a look-up table using one or more ofthose optical characteristics. In one example embodiment of theinvention, if the intensity of a given PUF 26 is above a predeterminedthreshold value, that PUF 26 may be assigned the numeral 1, but if theintensity is below the predetermined threshold value, that PUF 26 may beassigned to the numeral 0. The resulting string of 1's and 0's thusassociated with the PUFs 26 of the circuit 10 may then be compared to aplurality of strings of 1's and 0's stored in the circuit database 30 todetermine the authenticity of that circuit 10.

In some embodiments of the invention, the comparing step may furtherincluding determining, using the optical characteristics of each of thePUFs 26, at least one of an ion implant concentration, a quantity ofdislocation loops 22, how deep the ions 20 are implanted, how many atomsare implanted, and a size of area of each of the PUFs 26. Thisinformation may then be used in the assigning of the values for each ofthe PUFs. The values assigned to each of the PUFs may cooperatively forma circuit identifier. Thus, the comparing step 506 may includedetermining if the circuit identifier matches at least one of the groupsof values stored in the circuit database 30. As noted above, each of thegroups of stored values in the circuit database 30 may be associatedwith optical characteristics of PUFs of a known authentic circuit.

Finally, the method 500 may include a step of providing an indication ofwhether or not the integrated circuit 10 is authentic or counterfeit, asdepicted in block 508. When each of the values associated with thesensed optical characteristics of the PUFs 26 (i.e., the circuitidentifier) match the stored values of at least one of the groups in thecircuit database 30, then the controller 34 may audibly or visuallyindicate that the circuit 10 is authentic. Conversely, when each of thevalues associated with the sensed optical characteristics of the PUFs 26(i.e., the circuit identifier) do not match the stored values of atleast one of the groups in the circuit database 30, then the controller34 may audibly or visually indicate that the circuit 10 is acounterfeit. For example, the controller 30 may output authenticationinformation on the visual display device and/or speaker described aboveto notify the user that the circuit 10 is either authentic or wasdetermined by the controller 30 to be a counterfeit circuit.Alternatively, the controller 34 may only provide audible or visualfeedback to the user if the circuit 10 is determined to be authentic orconversely if the circuit 10 is determined to be counterfeit.

Embodiments of the invention described above may be used commercially toprevent counterfeiting of common electronics. It could also be used indefense applications to provide a simple test-and-detect method toensure a trusted supply chain for critical microelectronic devices. Whenapplied to different semiconductors, such as Si, SiGe, GaAs, and GaN,the implanting of ions could be tailored to that particular material toprovide optimum light output when electrically or optically stimulated.

Advantageously, by using ion implants and the associated damage, thePUFs 26 of the present invention require no on-chip power, no complexcircuitry, and can thus be used across multiple semiconductor platforms(e.g., Si, GaAs, GaN). Furthermore, because ion implants are a typicaland often trivial part of the semiconductor manufacturing process andare buried beneath a surface layer of the integrated circuit 10, it isnearly impossible for competitors or counterfeiters to detect thematerial PUFs 26 of the present invention. Likewise, small differencesin ion implant density are also nearly impossible to detect and evenharder to replicate.

Conversely, prior art electrical PUFs could only be used in Si CMOScircuitry, required operation of the integrated circuit to functionproperly, and thus required fabrication of complex integrated circuity,making it obvious that the device had been identified as importantenough to protect. The prior art electrical PUFs also suffer fromreliability issues when heated above 200 degrees Celsius.Advantageously, the material PUFs 26 of the present invention may bereliable up to 500 degrees Celsius, as the recovery process for defectshas a very high activation temperature.

Although the invention has been described with reference to theembodiments illustrated in the attached drawing figures, it is notedthat equivalents may be employed and substitutions made herein withoutdeparting from the scope of the invention as recited in the claims.

Having thus described various embodiments of the invention, what isclaimed as new and desired to be protected by Letters Patent includesthe following:

The invention claimed is:
 1. A method of authenticating an integratedcircuit, the method comprising: stimulating a defect area on theintegrated circuit, the defect area comprising high energy ionsimplanted into crystal lattices of semiconductor material of theintegrated circuit to form a PUF; sensing with an optical sensor anoptical characteristic of light emitted from the PUF when stimulated;and comparing, via a controller, a value associated with the opticalcharacteristic of the PUF with a stored value in a circuit database,wherein the stored value is associated with a previously-logged opticalcharacteristic of a PUF of a known authentic circuit.
 2. The method ofclaim 1, wherein the optical characteristics of the PUF of theintegrated circuit includes at least one of wavelength, intensity, andtotal area of the light received with the optical sensor from the PUF ofthe integrated circuit.
 3. The method of claim 1, wherein the opticalcharacteristic of the PUF of the integrated circuit is dependent upon atleast one of an implant concentration of ions that formed the PUF, aquantity of dislocation loops of the PUF, how deep the ions areimplanted, how many atoms are implanted in the PUF, or a size of area ofthe PUF.
 4. The method of claim 1, wherein the step of stimulatingincludes passing an electric current through the PUF.
 5. The method ofclaim 1, further comprising a plurality of defect areas cooperativelyproviding a numerical key serving as a circuit authentication identifierfor the integrated circuit, wherein the comparing step includescomparing the numerical key with a plurality of stored keys in thecircuit database.
 6. The method of claim 1, wherein the semiconductormaterial may comprise at least one of the following materials: Si, SiGe,GaAs, or GaN.
 7. The method of claim 1, wherein the ions implanted intothe crystal lattices are at least one of boron or phosphorus.
 8. Themethod of claim 1, further comprising providing, via the controller, anindication that the integrated circuit is a counterfeit circuit when thevalue associated with the optical characteristic of the PUF does notmatch the stored value in the circuit database.
 9. The method of claim1, wherein the stimulating the defect area comprises stimulating thedefect area without powering the integrated circuit.
 10. The method ofclaim 1, wherein the crystal lattices comprise doped semiconductormaterial so that the high energy ions and the doped semiconductormaterial cooperatively form line defects or dislocation loops.
 11. Amethod of reading physically unclonable functions (PUFs) on anintegrated circuit, the method comprising: stimulating the integratedcircuit, wherein the integrated circuit includes a plurality oflocations having high energy ions implanted into crystal lattices ofsemiconductor material of the integrated circuit, each location forminga PUF having unique optical characteristics when stimulated; sensingwith an optical sensor optical characteristics of light emitted from thePUFs when stimulated, wherein the optical characteristics of the PUFs ofthe integrated circuit include at least one of wavelength, intensity,and total area of the light received with the optical sensor from eachof the PUFs of the integrated circuit; using, via a controller, theoptical characteristics of the PUFs to determine at least one of animplant concentration of ions that formed the PUFs, a quantity ofdislocation loops of the PUFs, how deep the ions are implanted, how manyatoms are implanted in the PUFs, or a size of area of each of the PUFs;comparing, via the controller, values associated with the opticalcharacteristics of the PUFs with a group of stored values in a circuitdatabase, wherein the group of stored values is associated withpreviously-logged optical characteristics of PUFs of at least one knownauthentic circuit; and providing, via the controller, audible or visualindication of authenticity of the integrated circuit when the valuesassociated with the optical characteristics of the PUFs match the storedvalues of the group in the circuit database.
 12. The method of claim 11,further comprising a step of the controller assigning to each of thePUFs one of the values associated with the optical characteristics ofthe PUFs, wherein the assigning step includes solving an algorithm withat least one of the optical characteristics.
 13. The method of claim 11,wherein the step of stimulating includes photoexcitation of photons inone of the PUFs.
 14. The method of claim 11, wherein the plurality oflocations includes a number of discrete areas, cooperatively providing anumerical key serving as a circuit authentication identifier for thecircuit, wherein the comparing step includes comparing the numerical keywith a plurality of stored keys in the circuit database.
 15. The methodof claim 11, wherein the semiconductor material may comprise at leastone of the following materials: Si, SiGe, GaAs, or GaN.
 16. The methodof claim 11, wherein the ions implanted into the crystal lattices are atleast one of boron or phosphorus.
 17. The method of claim 11, furthercomprising an audible or visual indication, via the controller, that theintegrated circuit is a counterfeit circuit when the values associatedwith the optical characteristics of the PUFs do not match the storedvalues of the group in the circuit database.
 18. An authenticationapparatus comprising: a controller including a processor and memory,wherein the memory is a non-transitory computer-readable medium with acomputer program stored thereon, the computer program comprising: a codesegment for instructing an energy source to stimulate each of aplurality of PUFs, wherein the PUFs include high energy ions implantedinto crystal lattices of semiconductor material of the integratedcircuit at a plurality of locations, each location forming one of thePUFs; a code segment for receiving from an optical sensor opticalcharacteristics of light emitted from the PUFs when stimulated; a codesegment for determining, based on the optical characteristics of thePUFs of the integrated circuit, at least one of an implant concentrationof ions that formed the PUFs, a quantity of dislocation loops of thePUFs, how deep the ions are implanted, how many atoms are implanted inthe PUFs, or a size of area of each of the PUFs; and a code segment forcomparing values associated with the optical characteristics of the PUFswith a group of stored values in a circuit database, wherein the groupof stored values is associated with previously-logged opticalcharacteristics of PUFs of at least one known authentic circuit.
 19. Theauthentication apparatus of claim 18, further comprising the opticalsensor communicably coupled with the processor, wherein the opticalsensor is configured to sense the optical characteristics of the lightemitted from the PUFs when stimulated.
 20. The authentication apparatusof claim 18, wherein the memory of the controller further includes thecircuit database.